Many livestock producers employ automatic feeding systems for their livestock, sometimes a liquid feed in cases where there are younger animals such as piglets. In such cases, the liquid feed is often a form of milk replacer product, usually a mixture of dry powder and water. The feed may be either a dry milk replacer product or a condensed liquid feed product.
The milk delivery systems presently in use often comprise feeding units connected by pipelines to a reservoir tank, the pipelines providing a generally continuous circulating flow of liquid feed through the system, and the feeding units often include an animal-actuated valve mechanism to begin flow of the liquid feed into the feeding unit for consumption by the animal. In this way, liquid feed is supplied on an as-needed basis to the livestock and it does not become stagnant in the system while waiting for consumption.
U.S. Pat. No. 5,067,443 teaches a neonatal piglet nursing apparatus having a refrigerated storage tank to keep liquid feed fresh, but also having heating tanks to subsequently warm the liquid feed to body temperature before nursing to encourage consumption by the piglets. The apparatus is intended to provide a surrogate function, taking the place of a natural mother, and therefore attempts to simulate the natural feeding experience by, among other things, trying to match the temperature of a mother's natural milk.
PCT International Application Publication No. 97/15185 teaches an automatic feeder where again the liquid feed is stored in a refrigerated container but subsequently heated prior to delivery to young pig.
U.S. Pat. No. 5,138,980 teaches a temperature-regulated liquid animal feeder that, in colder environments, uses a heated feed reservoir to prevent freezing or, in warmer environments, uses a refrigerated reservoir to keep water cool or solid food fresh, to increase appeal to the animal.
U.S. Pat. No. 6,199,512 teaches a feed delivery system that includes a disinfecting station adapted to effect cleaning of a feeding station. The water used to formulate a powdered milk solution is heated by a hot water heater prior to entering a mix tank.
In the aforementioned prior art feeding systems, heating of the liquid feed may reduce the tendency of a piglet to favour a mother sow's natural milk in a situation where both the natural milk and the liquid feed are available. As the sow's colostrum or first milk has contents that are valuable to the healthy development of the piglets and are not found in conventional liquid feed, a high level of competition between the desirability of natural milk and liquid feed during the first day immediately following the farrow is undesirable. However, not providing any supplemental liquid feed during this period may even further decrease the likelihood of survival of undersized or weak piglets not able to compete for space at the mother's teat or decrease the fraction of survivor's within an oversized litter.
U.S. Pat. No. 5,115,764 teaches a milk delivery system that seeks to address the unique needs of a milk replacer product, employing a pump-driven system to prevent the liquid feed from becoming state by continuously circulating it through the system.
Prior art circulation-based liquid feed systems may be limited in the amount of liquid feed they can contain at any one time by the size of the reservoir in which mixing of the feed is carried out. With a relatively small mixing reservoir, such a system may therefore require significantly frequent refilling, while increasing the size of the mixing reservoir may be costly due to the added need for additional or enlarged mixing equipment. Also, these systems may experience a significant amount of waste as a result of a pressure differential occurring along the feed supply line, causing inappropriately high pressure at the first feeding station. This may lead to an excessive discharge rate of liquid feed at that first station, causing splashing of feed out of the unit and possibly startling the animal attempting to feed therefrom.
Cleaning of prior art liquid feeding systems with hot water solutions may require externally heating the water, or adding a separate reservoir to the system for that particular purpose, and may involve the use of toxic cleansers that must be thoroughly flushed from all surfaces prior to subsequent feeding from the system. The addition of a separate heating vessel might not be considered cost and space efficient, and the need to rinse away toxic substances after running a cleaning fluid through the system adds to the time and cost of cleaning the system.
From the forgoing, it will be appreciated that there is a desire for improved methods and systems for providing liquid feed to livestock.